A few festival necessities have remained the same since that rainy August weekend in 1969 – food, water and shelter, namely – while others have changed dramatically over the intervening half-century (do you have your automatically adjusting headlamp yet?). Which leads us to 'Roostock.

The rules are simple. First, take a close look at each photograph. Next, digest our whimsical captioning. Then, decide if the picture was captured at Woodstock or one of the past 11 Bonnaroos. Once you've made up your mind, click to reveal the answer.